// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "net/base/expiring_cache.h"

#include <functional>
#include <string>

#include "base/stl_util.h"
#include "base/strings/stringprintf.h"
#include "base/time/time.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"

using testing::Pointee;
using testing::StrEq;

namespace net {

namespace {

    const int kMaxCacheEntries = 10;
    typedef ExpiringCache<std::string, std::string, base::TimeTicks,
        std::less<base::TimeTicks>>
        Cache;

    struct TestFunctor {
        bool operator()(const std::string& now,
            const std::string& expiration) const
        {
            return now != expiration;
        }
    };

} // namespace

TEST(ExpiringCacheTest, Basic)
{
    const base::TimeDelta kTTL = base::TimeDelta::FromSeconds(10);

    Cache cache(kMaxCacheEntries);

    // Start at t=0.
    base::TimeTicks now;
    EXPECT_EQ(0U, cache.size());

    // Add an entry at t=0
    EXPECT_FALSE(cache.Get("entry1", now));
    cache.Put("entry1", "test1", now, now + kTTL);
    EXPECT_THAT(cache.Get("entry1", now), Pointee(StrEq("test1")));
    EXPECT_EQ(1U, cache.size());

    // Advance to t=5.
    now += base::TimeDelta::FromSeconds(5);

    // Add an entry at t=5.
    EXPECT_FALSE(cache.Get("entry2", now));
    cache.Put("entry2", "test2", now, now + kTTL);
    EXPECT_THAT(cache.Get("entry2", now), Pointee(StrEq("test2")));
    EXPECT_EQ(2U, cache.size());

    // Advance to t=9.
    now += base::TimeDelta::FromSeconds(4);

    // Verify that the entries added are still retrievable and usable.
    EXPECT_THAT(cache.Get("entry1", now), Pointee(StrEq("test1")));
    EXPECT_THAT(cache.Get("entry2", now), Pointee(StrEq("test2")));

    // Advance to t=10; entry1 is now expired.
    now += base::TimeDelta::FromSeconds(1);

    EXPECT_FALSE(cache.Get("entry1", now));
    EXPECT_THAT(cache.Get("entry2", now), Pointee(StrEq("test2")));

    // The expired element should no longer be in the cache.
    EXPECT_EQ(1U, cache.size());

    // Update entry1 so it is no longer expired.
    cache.Put("entry1", "test1", now, now + kTTL);

    // Both entries should be retrievable and usable.
    EXPECT_EQ(2U, cache.size());
    EXPECT_THAT(cache.Get("entry1", now), Pointee(StrEq("test1")));
    EXPECT_THAT(cache.Get("entry2", now), Pointee(StrEq("test2")));

    // Advance to t=20; both entries are now expired.
    now += base::TimeDelta::FromSeconds(10);

    EXPECT_FALSE(cache.Get("entry1", now));
    EXPECT_FALSE(cache.Get("entry2", now));
}

TEST(ExpiringCacheTest, Compact)
{
    const base::TimeDelta kTTL = base::TimeDelta::FromSeconds(10);

    Cache cache(kMaxCacheEntries);

    // Start at t=0.
    base::TimeTicks now;
    EXPECT_EQ(0U, cache.size());

    // Add five valid entries at t=10 that expire at t=20.
    base::TimeTicks t10 = now + kTTL;
    for (int i = 0; i < 5; ++i) {
        std::string name = base::StringPrintf("valid%d", i);
        cache.Put(name, "I'm valid!", t10, t10 + kTTL);
    }
    EXPECT_EQ(5U, cache.size());

    // Add three entries at t=0 that expire at t=10.
    for (int i = 0; i < 3; ++i) {
        std::string name = base::StringPrintf("expired%d", i);
        cache.Put(name, "I'm expired.", now, t10);
    }
    EXPECT_EQ(8U, cache.size());

    // Add two negative (instantly expired) entries at t=0 that expire at t=0.
    for (int i = 0; i < 2; ++i) {
        std::string name = base::StringPrintf("negative%d", i);
        cache.Put(name, "I was never valid.", now, now);
    }
    EXPECT_EQ(10U, cache.size());

    EXPECT_TRUE(ContainsKey(cache.entries_, "valid0"));
    EXPECT_TRUE(ContainsKey(cache.entries_, "valid1"));
    EXPECT_TRUE(ContainsKey(cache.entries_, "valid2"));
    EXPECT_TRUE(ContainsKey(cache.entries_, "valid3"));
    EXPECT_TRUE(ContainsKey(cache.entries_, "valid4"));
    EXPECT_TRUE(ContainsKey(cache.entries_, "expired0"));
    EXPECT_TRUE(ContainsKey(cache.entries_, "expired1"));
    EXPECT_TRUE(ContainsKey(cache.entries_, "expired2"));
    EXPECT_TRUE(ContainsKey(cache.entries_, "negative0"));
    EXPECT_TRUE(ContainsKey(cache.entries_, "negative1"));

    // Shrink the new max constraints bound and compact. The "negative" and
    // "expired" entries should be dropped.
    cache.max_entries_ = 6;
    cache.Compact(now);
    EXPECT_EQ(5U, cache.size());

    EXPECT_TRUE(ContainsKey(cache.entries_, "valid0"));
    EXPECT_TRUE(ContainsKey(cache.entries_, "valid1"));
    EXPECT_TRUE(ContainsKey(cache.entries_, "valid2"));
    EXPECT_TRUE(ContainsKey(cache.entries_, "valid3"));
    EXPECT_TRUE(ContainsKey(cache.entries_, "valid4"));
    EXPECT_FALSE(ContainsKey(cache.entries_, "expired0"));
    EXPECT_FALSE(ContainsKey(cache.entries_, "expired1"));
    EXPECT_FALSE(ContainsKey(cache.entries_, "expired2"));
    EXPECT_FALSE(ContainsKey(cache.entries_, "negative0"));
    EXPECT_FALSE(ContainsKey(cache.entries_, "negative1"));

    // Shrink further -- this time the compact will start dropping valid entries
    // to make space.
    cache.max_entries_ = 4;
    cache.Compact(now);
    EXPECT_EQ(3U, cache.size());
}

// Add entries while the cache is at capacity, causing evictions.
TEST(ExpiringCacheTest, SetWithCompact)
{
    const base::TimeDelta kTTL = base::TimeDelta::FromSeconds(10);

    Cache cache(3);

    // t=10
    base::TimeTicks now = base::TimeTicks() + kTTL;

    cache.Put("test1", "test1", now, now + kTTL);
    cache.Put("test2", "test2", now, now + kTTL);
    cache.Put("expired", "expired", now, now);

    EXPECT_EQ(3U, cache.size());

    // Should all be retrievable except "expired".
    EXPECT_THAT(cache.Get("test1", now), Pointee(StrEq("test1")));
    EXPECT_THAT(cache.Get("test2", now), Pointee(StrEq("test2")));
    EXPECT_FALSE(cache.Get("expired", now));

    // Adding the fourth entry will cause "expired" to be evicted.
    cache.Put("test3", "test3", now, now + kTTL);
    EXPECT_EQ(3U, cache.size());

    EXPECT_FALSE(cache.Get("expired", now));
    EXPECT_THAT(cache.Get("test1", now), Pointee(StrEq("test1")));
    EXPECT_THAT(cache.Get("test2", now), Pointee(StrEq("test2")));
    EXPECT_THAT(cache.Get("test3", now), Pointee(StrEq("test3")));

    // Add two more entries. Something should be evicted, however "test5"
    // should definitely be in there (since it was last inserted).
    cache.Put("test4", "test4", now, now + kTTL);
    EXPECT_EQ(3U, cache.size());
    cache.Put("test5", "test5", now, now + kTTL);
    EXPECT_EQ(3U, cache.size());
    EXPECT_THAT(cache.Get("test5", now), Pointee(StrEq("test5")));
}

TEST(ExpiringCacheTest, Clear)
{
    const base::TimeDelta kTTL = base::TimeDelta::FromSeconds(10);

    Cache cache(kMaxCacheEntries);

    // Start at t=0.
    base::TimeTicks now;
    EXPECT_EQ(0U, cache.size());

    // Add three entries.
    cache.Put("test1", "foo", now, now + kTTL);
    cache.Put("test2", "foo", now, now + kTTL);
    cache.Put("test3", "foo", now, now + kTTL);
    EXPECT_EQ(3U, cache.size());

    cache.Clear();

    EXPECT_EQ(0U, cache.size());
}

TEST(ExpiringCacheTest, GetTruncatesExpiredEntries)
{
    const base::TimeDelta kTTL = base::TimeDelta::FromSeconds(10);

    Cache cache(kMaxCacheEntries);

    // Start at t=0.
    base::TimeTicks now;
    EXPECT_EQ(0U, cache.size());

    // Add three entries at t=0.
    cache.Put("test1", "foo1", now, now + kTTL);
    cache.Put("test2", "foo2", now, now + kTTL);
    cache.Put("test3", "foo3", now, now + kTTL);
    EXPECT_EQ(3U, cache.size());

    // Ensure the entries were added.
    EXPECT_THAT(cache.Get("test1", now), Pointee(StrEq("foo1")));
    EXPECT_THAT(cache.Get("test2", now), Pointee(StrEq("foo2")));
    EXPECT_THAT(cache.Get("test3", now), Pointee(StrEq("foo3")));

    // Add five entries at t=10.
    now += kTTL;
    for (int i = 0; i < 5; ++i) {
        std::string name = base::StringPrintf("valid%d", i);
        cache.Put(name, name, now, now + kTTL); // Expire at t=20.
    }
    EXPECT_EQ(8U, cache.size());

    // Now access two expired entries and ensure the cache size goes down.
    EXPECT_FALSE(cache.Get("test1", now));
    EXPECT_FALSE(cache.Get("test2", now));
    EXPECT_EQ(6U, cache.size());

    // Accessing non-expired entries should return entries and not adjust the
    // cache size.
    for (int i = 0; i < 5; ++i) {
        std::string name = base::StringPrintf("valid%d", i);
        EXPECT_THAT(cache.Get(name, now), Pointee(StrEq(name)));
    }
    EXPECT_EQ(6U, cache.size());
}

TEST(ExpiringCacheTest, CustomFunctor)
{
    ExpiringCache<std::string, std::string, std::string, TestFunctor> cache(5);

    const std::string kNow("Now");
    const std::string kLater("A little bit later");
    const std::string kMuchLater("Much later");
    const std::string kHeatDeath("The heat death of the universe");

    EXPECT_EQ(0u, cache.size());

    // Add three entries at t=kNow that expire at kLater.
    cache.Put("test1", "foo1", kNow, kLater);
    cache.Put("test2", "foo2", kNow, kLater);
    cache.Put("test3", "foo3", kNow, kLater);
    EXPECT_EQ(3U, cache.size());

    // Add two entries at t=kNow that expire at kMuchLater
    cache.Put("test4", "foo4", kNow, kMuchLater);
    cache.Put("test5", "foo5", kNow, kMuchLater);
    EXPECT_EQ(5U, cache.size());

    // Ensure the entries were added.
    EXPECT_THAT(cache.Get("test1", kNow), Pointee(StrEq("foo1")));
    EXPECT_THAT(cache.Get("test2", kNow), Pointee(StrEq("foo2")));
    EXPECT_THAT(cache.Get("test3", kNow), Pointee(StrEq("foo3")));
    EXPECT_THAT(cache.Get("test4", kNow), Pointee(StrEq("foo4")));
    EXPECT_THAT(cache.Get("test5", kNow), Pointee(StrEq("foo5")));

    // Add one entry at t=kLater that expires at kHeatDeath, which will expire
    // one of test1-3.
    cache.Put("test6", "foo6", kLater, kHeatDeath);
    EXPECT_THAT(cache.Get("test6", kLater), Pointee(StrEq("foo6")));
    EXPECT_EQ(3U, cache.size());

    // Now compact at kMuchLater, which should remove all but "test6".
    cache.max_entries_ = 2;
    cache.Compact(kMuchLater);

    EXPECT_EQ(1U, cache.size());
    EXPECT_THAT(cache.Get("test6", kMuchLater), Pointee(StrEq("foo6")));

    // Finally, "test6" should not be valid at the end of the universe.
    EXPECT_FALSE(cache.Get("test6", kHeatDeath));

    // Because comparison is based on equality, not strict weak ordering, we
    // should be able to add something at kHeatDeath that expires at kMuchLater.
    cache.Put("test7", "foo7", kHeatDeath, kMuchLater);
    EXPECT_EQ(1U, cache.size());
    EXPECT_THAT(cache.Get("test7", kNow), Pointee(StrEq("foo7")));
    EXPECT_THAT(cache.Get("test7", kLater), Pointee(StrEq("foo7")));
    EXPECT_THAT(cache.Get("test7", kHeatDeath), Pointee(StrEq("foo7")));
    EXPECT_FALSE(cache.Get("test7", kMuchLater));
}

} // namespace net
